Running on muffs

Me Too

Cadet
Joined
Nov 8, 2019
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8
Since I'm new to boats, I ask a lot of stupid questions so bear with me. Testing the motor on a garden hose with muffs and was told not to run the motor above about 1500 rpm. Is this true?
 

achris

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May 19, 2004
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24,848
Yes. As the engine speed increases so too does the water pump impeller speed. A standard garden hose can't supply enough water beyond about 1500rpm, so you'll end up with a burnt impeller....

Oh, and don't worry about asking too many questions. The only dumb question is the one asked too late...

Chris....
 

Me Too

Cadet
Joined
Nov 8, 2019
Messages
8
Thanks! I ran it up briefly to 2k but I won't go beyond that. Of course I do plan on replacing the impeller anyway.
 

Me Too

Cadet
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Nov 8, 2019
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8
Which brings up another question. I don't have a serial number for the outdrive so how do I know which impeller to buy? I see whole pump kits with the housing and all new parts. I only need just the impeller correct? Drive only has about 150 hours on it.
 

achris

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Got a serial number for the engine? Or a year?
 

Me Too

Cadet
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Nov 8, 2019
Messages
8
2001 Sea Ray 180 with 3.0 but, the outdrive is from a 2002. New motor also.
 

Scott Danforth

Grumpy old guy who plays with boats
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Jul 23, 2011
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33,384
Drive only has about 150 hours on it.

impellers dont care how many hours there are on the hour meter. that is only how many hours you used the boat.

rubber parts go off of calendar time. doesnt mater if you use the boat or not. impellers get replaced every 5 years in fresh water, or about every 3 years in salt water.
 

achris

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impellers dont care how many hours there are on the hour meter. that is only how many hours you used the boat.

rubber parts go off of calendar time. doesnt mater if you use the boat or not. impellers get replaced every 5 years in fresh water, or about every 3 years in salt water.

I'll add to that....

Using the boat more will decrease the likelihood of a fail in the interim. Rubber parts like nothing less than sitting around doing nothing. Keep using them on a regular basis and they stay pliable and are less prone to premature failure.

"It's not USING a boat that damages it, it NOT using a boat that damages it."

Chris............
 

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
Messages
33,384
lets look at it another way. you have a 19 year old boat with 150 hours on it. that is less than 8 hours of use per year, or basically once a year.

it should have 950 hours on it if it was used the average amount which is 50 hours per year.

use the boat
 
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